Add GrpcWeb middleware

Co-authored-by: Kevin Pollet <pollet.kevin@gmail.com>

docs/content/middlewares/http/grpcweb.md

@@ -0,0 +1,77 @@
+---
+title: "Traefik GrpcWeb Documentation"
+description: "In Traefik Proxy's HTTP middleware, GrpcWeb converts a gRPC Web requests to HTTP/2 gRPC requests. Read the technical documentation."
+---
+
+# GrpcWeb
+
+Converting gRPC Web requests to HTTP/2 gRPC requests.
+{: .subtitle }
+
+The GrpcWeb middleware converts gRPC Web requests to HTTP/2 gRPC requests before forwarding them to the backends.
+
+!!! tip
+
+    Please note, that Traefik needs to communicate using gRPC with the backends (h2c or HTTP/2 over TLS).
+    Check out the [gRPC](../../user-guides/grpc.md) user guide for more details.
+
+## Configuration Examples
+
+```yaml tab="Docker"
+labels:
+  - "traefik.http.middlewares.test-grpcweb.grpcweb.allowOrigins=*"
+```
+
+```yaml tab="Kubernetes"
+apiVersion: traefik.containo.us/v1alpha1
+kind: Middleware
+metadata:
+  name: test-grpcweb
+spec:
+  grpcWeb:
+    allowOrigins:
+      - "*"
+```
+
+```yaml tab="Consul Catalog"
+- "traefik.http.middlewares.test-grpcweb.grpcWeb.allowOrigins=*"
+```
+
+```json tab="Marathon"
+"labels": {
+  "traefik.http.middlewares.test-grpcweb.grpcweb.alloworigins": "*"
+}
+```
+
+```yaml tab="Rancher"
+labels:
+  - "traefik.http.middlewares.test-grpcweb.grpcweb.alloworigins=*"
+```
+
+```yaml tab="File (YAML)"
+http:
+  middlewares:
+    test-grpcweb:
+      grpcWeb:
+        allowOrigins:
+          - "*"
+```
+
+```toml tab="File (TOML)"
+[http.middlewares]
+  [http.middlewares.test-grpcweb.grpcWeb]
+    allowOrigins = ["*"]
+```
+
+## Configuration Options
+
+### `allowOrigins`
+
+The `allowOrigins` contains the list of allowed origins.
+A wildcard origin `*` can also be configured to match all requests.
+
+More information including how to use the settings can be found at:
+
+- [Mozilla.org](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Access-Control-Allow-Origin)
+- [w3](https://fetch.spec.whatwg.org/#http-access-control-allow-origin)
+- [IETF](https://tools.ietf.org/html/rfc6454#section-7.1)

docs/content/reference/dynamic-configuration/docker-labels.yml

@@ -121,6 +121,7 @@
 - "traefik.http.middlewares.middleware21.stripprefix.forceslash=true"
 - "traefik.http.middlewares.middleware21.stripprefix.prefixes=foobar, foobar"
 - "traefik.http.middlewares.middleware22.stripprefixregex.regex=foobar, foobar"
+- "traefik.http.middlewares.middleware23.grpcweb.alloworigins=foobar, foobar"
 - "traefik.http.routers.router0.entrypoints=foobar, foobar"
 - "traefik.http.routers.router0.middlewares=foobar, foobar"
 - "traefik.http.routers.router0.priority=42"

docs/content/reference/dynamic-configuration/file.toml

@@ -285,6 +285,9 @@
     [http.middlewares.Middleware22]
       [http.middlewares.Middleware22.stripPrefixRegex]
         regex = ["foobar", "foobar"]
+    [http.middlewares.Middleware23]
+      [http.middlewares.Middleware23.grpcWeb]
+        allowOrigins = ["foobar", "foobar"]
   [http.serversTransports]
     [http.serversTransports.ServersTransport0]
       serverName = "foobar"

docs/content/reference/dynamic-configuration/file.yaml

@@ -324,6 +324,11 @@ http:
         regex:
           - foobar
           - foobar
+    Middleware23:
+      grpcWeb:
+        allowOrigins:
+          - foobar
+          - foobar
   serversTransports:
     ServersTransport0:
       serverName: foobar

docs/content/reference/dynamic-configuration/kubernetes-crd-definition-v1.yml

@@ -967,6 +967,17 @@ spec:
                       forward) all X-Forwarded-* headers.'
                     type: boolean
                 type: object
+              grpcWeb:
+                description: GrpcWeb holds the gRPC web middleware configuration.
+                  This middleware converts a gRPC web request to an HTTP/2 gRPC request.
+                properties:
+                  allowOrigins:
+                    description: AllowOrigins is a list of allowable origins. Can
+                      also be a wildcard origin "*".
+                    items:
+                      type: string
+                    type: array
+                type: object
               headers:
                 description: 'Headers holds the headers middleware configuration.
                   This middleware manages the requests and responses headers. More

docs/content/reference/dynamic-configuration/kv-ref.md

@@ -140,6 +140,8 @@
 | `traefik/http/middlewares/Middleware21/stripPrefix/prefixes/1` | `foobar` |
 | `traefik/http/middlewares/Middleware22/stripPrefixRegex/regex/0` | `foobar` |
 | `traefik/http/middlewares/Middleware22/stripPrefixRegex/regex/1` | `foobar` |
+| `traefik/http/middlewares/Middleware23/grpcWeb/allowOrigins/0` | `foobar` |
+| `traefik/http/middlewares/Middleware23/grpcWeb/allowOrigins/1` | `foobar` |
 | `traefik/http/routers/Router0/entryPoints/0` | `foobar` |
 | `traefik/http/routers/Router0/entryPoints/1` | `foobar` |
 | `traefik/http/routers/Router0/middlewares/0` | `foobar` |

docs/content/reference/dynamic-configuration/marathon-labels.json

@@ -121,6 +121,7 @@
 "traefik.http.middlewares.middleware21.stripprefix.forceslash": "true",
 "traefik.http.middlewares.middleware21.stripprefix.prefixes": "foobar, foobar",
 "traefik.http.middlewares.middleware22.stripprefixregex.regex": "foobar, foobar",
+"traefik.http.middlewares.middleware23.grpcweb.alloworigins": "foobar, foobar",
 "traefik.http.routers.router0.entrypoints": "foobar, foobar",
 "traefik.http.routers.router0.middlewares": "foobar, foobar",
 "traefik.http.routers.router0.priority": "42",

docs/content/reference/dynamic-configuration/traefik.containo.us_middlewares.yaml

@@ -390,6 +390,17 @@ spec:
                       forward) all X-Forwarded-* headers.'
                     type: boolean
                 type: object
+              grpcWeb:
+                description: GrpcWeb holds the gRPC web middleware configuration.
+                  This middleware converts a gRPC web request to an HTTP/2 gRPC request.
+                properties:
+                  allowOrigins:
+                    description: AllowOrigins is a list of allowable origins. Can
+                      also be a wildcard origin "*".
+                    items:
+                      type: string
+                    type: array
+                type: object
               headers:
                 description: 'Headers holds the headers middleware configuration.
                   This middleware manages the requests and responses headers. More